Filtration and Decantation - Technique, Application, Advantages, Disadvantages, Examples, Practice Problems, FAQs

Have you ever considered what might happen if oil is accidentally poured into the water? Is it possible to get that oil back from the water? The answer is yes, we can separate oil from water by decantation.

As oil and water are immiscible, water is denser than oil and forms two separate layers. By using a separating funnel, it is easy to separate oil and water.

What is the need to study filtration and decantation?

It plays an important role in practical chemistry to separate immiscible liquids and suspension.

Table of content:

Filtration
Types of Filtration
Application of Filtration
Decantation
Decantation Procedure
Decantation vs Filtration
Advantages of Decantation
Disadvantages of Decantation
Examples of Decantation
Practice Problems
Frequently asked questions

Filtration

Filtration is a simple process of separation, which is used to separate particulate matter from a fluid mixture. In this case, either the separated solid particle or the fluid obtained after filtration can be the compound of interest. Before the advancement and development of water purifiers, muddy water was separated by the process of filtration.

There are four main components needed to efficiently perform the process of filtration:

1. The liquid mixture is suspended with solid particles.
2. A filter medium

This is an important component in the filtration process, as it serves as the barrier that would allow only the liquid to pass through it. The medium can be thin, for example, muslin cloth, filter paper, or thick, for example, sand bed and porous ceramic.

3. Any kind of force that would allow the fluid to flow through the filtration medium.

This force can be gravitational, centrifugal, pressure or vacuum, and will drive the liquid to flow through the filter media and undergo separation. In the laboratory, sometimes the liquid is allowed to trickle under the force of gravity; however, it is time-consuming and hence, not recommended.

4. A mechanical device to hold the entire apparatus together.

Types of Filtration

Based on the conditions in which a particular filtration process is performed, the various types of filtration are as follows:

Gravity filtration
Vacuum filtration
Centrifugal filtration
Hot filtration
Cold filtration
Mechanical filtration
Conventional filtration

Application of Filtration

In sewage treatment plants, to treat the effluents collected from various chemical industries before letting it out into the water bodies.
In the brewing industry, the process of clarification is based on the principles of filtration.
In the automotive industry, filtration is used to clear out any pipes or tubes used. This would increase the durability and prevent corrosion of the tube.
HEPA filter, a kind of mechanical air filter, is used to remove suspended dust particles, viruses, and microbes from the air.

Decantation

Decantation is the separation of liquid from solids and other immiscible (non-mixing) liquids by separating the liquid layer on top from the solid or liquid layer below.

This method can also be used to separate two non-mixing liquids, such as oil and water. When we maintain the oil and water mixture in a container, we get two distinct layers, with the water at the bottom and the lighter oil at the top. The oil layer on top can be poured into a different vessel, leaving the water layer at the bottom.

If we leave a bucket of water with sand or mud in it for a while, we'll see that the insoluble particles settle to the bottom of the bucket. The term "immiscible liquid" refers to liquids that do not mix to produce a solution.

Decantation Procedure

There are two procedures for Decantation -

1. Immiscible Liquid Separation

Decantation is a technique that is used to separate two liquids with different densities. When water and oil are mixed, for example, they divide into two layers. Because water is denser than oil, it sinks to the bottom while oil floats on top. You can also use a funnel to separate it. It permits two immiscible liquids to be effectively separated.

2. Liquid-Solid Separation

Decantation also aids in the separation of insoluble particles from liquid. In the laboratory, this procedure is utilized. To allow sedimentation, the test tube is heated to 45 degrees.

Example grease on the top of the soup, mud, a mixture of oil and water, liquid from mustard.

Decantation vs Filtration

To extract particulate impurities from liquids, both filtration and decantation are utilized. Filtration is the process of separating the entire solution through the use of a filter. The filter traps the solid particles and allows liquid to pass through. Decantation is the process of separating liquid from solid impurities that have accumulated at the bottom of a container.

Advantages of Decantation

It is an easy process
It can be performed manually
It can easily separate immiscible liquids

Disadvantages of Decantation

It cannot separate solids or liquids that dissolve in a mixture
It cannot separate salt from water
It is unable to extract impurities from water, such as chalk powder.
It cannot remove tiny impurities
It cannot remove microscopic impurities

Examples of Decantation

The decantation process is helpful in our daily lives in many ways. Here are some examples of this process.

To avoid losing flavour, red wine is decanted from a crystal of potassium bitartrate.
The cream that has risen to the top of the milk is decanted. It permits cream and milk to be separated. In the cheese industry, this is used.
To acquire a sample of water, muddy water is moved to another container.
Decantation plays an important role in nanotechnology.
It is used to cleanse liquids by removing insoluble particles from the sediment.
It is used in the sugar industry to granular sugarcane into sugar
It permits lipids to be removed from source materials during the grape vinegar production process.
When doing diagnostic testing, it is used to separate plasma from the blood.
The froth flotation method makes use of it. The froth flotation method is a separation procedure that separates hydrophobic and hydrophilic components from one another.
Mercury is sometimes dumped in bodies of water, resulting in hazardous water that is unfit for human consumption. The procedure of Decantation is used to eliminate mercury.

Practice Problems

Q 1.What is the easy way of separating sand from water?

1. Sieving
2. Filtration
3. Evaporation
4. Sedimentation and decantation

Answer: D)

Sieving and evaporation is not a method to separate sand from water and filtration also separates the sand from water but it involves filter paper in which sand particles remain on the filter paper.

The easiest way to separate sand from water is sedimentation and decantation, keep the sand water mixture for a long, sand particles will settle down, and then by decantation, easily water can be removed.

Q 2.Which is obtained in a pure form from a solution?

1. Solid
2. Liquid
3. Gas
4. Solid-Liquid

Answer: B)

Liquid is obtained in a pure from solution by various purification and separation techniques which are crystallization, decantation, distillation, etc.

Q 3.Which of the following process is used to separate a solid which is dissolved in liquid?

1. Sedimentation
2. Filtration
3. Evaporation
4. decantation

Solution: C)

Evaporation is the process that is used to separate a dissolved solid from a liquid.

Example: salt from seawater.

Q 4.Which process is used to separate butter from milk?

1. Sedimentation
2. Churning
3. Decantation
4. filtration

Solution: B

Churning process is used to separate butter by shaking whole milk or cream with a butter churn. And then by decantation or filtration

Frequently asked questions

Q 1. What is decantation?
Answer: Decantation is the separation of liquid from solids and other immiscible (non-mixing) liquids.

Q 2. Define Loading?
Answer: Loading is the technique of separating mixtures of liquids and liquids containing microscopic impurities by adding a chemical to the impurities that adhere to them and makes them heavier.

Q 3. Give one example of decantation?
Answer: Cream present on top of the milk is decanted. It allows the separation of cream and milk. This is used in the cheese industry.

Q 4. Can we separate two miscible liquids using decantation?
Answer: No, decantation is used for non-mixing liquids. For miscible liquids, distillation is used.

Q 5. Are decantation and sedimentation the same?
Answer: Sedimentation involves two phases one is solid and one is liquid but in decantation two phases can be solid-liquid or liquid-liquid.

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